Absidia stercoraria Hyang B. Lee, H.S. Lee & T.T.T. Nguyen, sp. nov.
MycoBank number: MB 814409, Facesoffungi number: FoF 02064, Fig. 2
Etymology – stercoraria. Named for rat dung from which the species was first collected.
Holotype – EML-DG8-1, deposited at the Environmental Microbiology Laboratory Fungarium, Chonnam National University, Gwangju, Korea. Living culture CNUFC-EMLDG8-1, in Chonnam National University Fungal Collection, Gwangju, Korea.

Colonies exhibit rapid growth on SMA attaining a diam. of 85 – 90 mm after 5 days at 25 °C, initial colour white, later changing to grayish – white or smoky – gray, the reverse white and irregularly zonate. Sporangiophores are 4 – 6 μm wide and arise as 1 – 5 sporangiophores (average 2–3) per whorl from a single point on the stolons. Sporangia 19 – 30 × 20 – 31 μm, globose to pyriform, multi-spored, frequently with a bell-shaped apophysis. Columellae are 9 – 13 × 12 – 13. 5 μm, hemisphaerical. Collarette appearing after sporangium maturation. Sporangiospores mostly short cylindrical, 4 – 5 × 2 – 3 μm. Zygospores not observed and rhizoids not well developed.

Notes – Absidia stercoraria is morphologically similar to A. koreana, but apparently differs from the related species by having a bell-shaped apophysis when cultivated on SMA, and by multi-gene sequence data. It is currently known from a single collection.

Material examined – REPUBLIC OF KOREA, Division of Food Technology, Biotechnology & Agrochemistry, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Korea, from rat dung sample from Gwangju, Korea; EML-DG8-1 (ex-type) at Culture Collection of National Institute of Biological Resources (NIBR), Incheon, and preserved as glycerol stock at -80 °C in the CNUFC; living culture(ex-type) deposited at Jena Microbial Resource Collection (University of Jena and Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany) (JMRC:SF:012179) (ex-type).

The isolate was observed to grow over a wide range of temperatures with varying growth rates of 18 mm, 14 mm, and 13 mm per 24 h on SMA, PDA and MEA, respectively. Optimal growth was observed around 25 – 27 °C, slow growth was observed down to 20 °C, and no growth above 35 °C. Absidia stercoraria appears to be phylogenetically related to A. koreana, both clustering in the same clade together with other Absidia spp. within the family Cunninghamellaceae (Fig. 1).

Fig. 1 Phylogenetic tree for Absidia stercoraria EML-DG8-1 and EML-DG8-2 and related species based on Maximum likelihood analysis of multi-genes including 18S and 28S rDNA, actin (Actin-1) and translation elongation factor (EF-1α). Sequences of Umbelopsis nana and U. isabellina were used as outgroups. Bootstrap support values >50 % are indicated at the nodes. The bar indicates the number of substitutions per position. New taxa are in blue and ex-type strains in bold.

Fig. 2 Absidia stercoraria (holotype) a, b Colony in synthetic mucor agar (a obverse view, b reverse view) c, d Young sporangia with sporangial net wall e Young sporangium with a bell-shaped apophysis (red arrow) f, g Mature sporangia with bell-shaped apophysis h Mature sporangium without bell-shaped apophysis i Columellae with collarette and a single projection (yellow arrow), and septum (white arrow) below the apophysis j, k Rod-shaped sporangiospores. Scale bars: c, d = 10 μm, f – i = 20 μm, j, k = 5 μm.